The 3.4 MHz High pass filter is useful to prevent overloading of wide-band receivers like my Multiband WSPR Receiver - model number #1055

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More specifically the filter will attenuate nearby AM transmitters in the medium wave band between 0.5 and 1.5MHz

Practical test have shown good effect on receivers that experience blocking effect due to local AM transmitters. After fitting of the filter the blocking dissapers and the receiver regained normal performance in 3.5 to 30MHz range.

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The performance if the filter is good in the pass band, the trough loss is less than 1dB on most frequencies so it wont affect receiver performance.

The cut-off frequency were then filter has 3dB loss is around 3.3 to 3.6MHz.

The attenuation increases as the frequency goes below the cut-off frequency and at 1.5MHz the loss or attenuation is around 58dB.

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The filter comes as a kit were the user have to do some light assembly before it can be used - see assembly guide PDF above.
 

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